Last Week Tonight returned from its hiatus on Sunday and, with less than 24 hours before the first presidential debate, John Oliver turned his focus to the ethical issues surrounding candidates Hillary Clinton and Donald Trump.

He said that this election has so far been "defined by ethics more than policy" and pointed to polls showing that less than half of the electorate think either candidate is trustworthy.

Starting with Clinton, Oliver said, “I do know that even talking about her scandals will irritate some of you, given that her opponent is an unambiguously racist scarecrow stuffed with scrunched up copies of Juggs magazine. And that's fair. That is a fair point. But not being as bad as Donald Trump is a low bar to clear.”

The host pointed out that it's important to not just focus on Trump but also to thoroughly vet the woman who might become president of the United States. "If you believe the internet, she's guilty of everything," said Oliver, going through some of the Hillary Clinton conspiracy theories.

Bringing out stacks of papers on Clinton's heavily litigated scandals, Oliver talked about Whitewater and Benghazi before making up a scandal completely to illustrate the tone of coverage surrounding Clinton. He went in depth on Clinton's email scandal — at one point joking that she "stored government records on something Bill called the Porn Master 5000" — and the Clinton Foundation controversy.

"We've spent several frustrating weeks trawling through all the innuendo and exaggerations surrounding her email and foundation scandals, and the worst thing you can say is they both look bad, but the harder you look, the less you actually find," said Oliver.

Next he moved on to "America’s Wealthiest Hemorrhoid” Donald Trump. Oliver detailed Trump's refusal to release his tax returns, his lack of understanding about what a blind trust is and the Trump Foundation's use of charitable donations to settle Trump's lawsuits and to buy portraits of Trump.

Oliver said that it's dangerous to think there has been an equal number of scandals for both Trump and Clinton.

"Think of it like this: Ethical failings in a politician are like raisins in a cookie," said Oliver. "They shouldn't be there. They disgust people. But most politicians have at least a few raisins."

Continuing the metaphor, he said Clinton "arguably has more raisins than average" and held up a cookie saying, "There's probably 10 of these little f—ers in there."

"When it comes to Donald Trump, this is the amount of raisins that he represents," he continued, as raisins poured down onto Oliver and his desk.

"The man is a f—ing raisin monsoon. He is ethically compromised to an almost unprecedented degree," said Oliver as the raisins continued to rain down. "So if you don't like raisins, I get it — they're disgusting. But unfortunately, this November, you're going to have to swallow 10 or we're all going to be eating this shit for years."